Startups and marketers track week-over-week growth to spot trends quickly. Y Combinator famously suggests 5–7% weekly growth as a strong target for early startups – which compounds to 12–33× a year.
How to use the Week over Week Calculator
- Value in the initial week
- Value in the following week
- Value after several weeks
- Number of weeks between initial and that value
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the value in the first week and the following week, and optionally a value several weeks later.
Tips
- Use the nominal annual rate and pick the compounding frequency your bank or broker states.
- Small differences in return or fees compound into large differences over decades.
- Run the calculation with a cautious, a central and an optimistic return to see the range of outcomes.
- Past returns do not guarantee future returns – nothing here is investment advice.
Common mistakes to avoid
- Comparing an APR with an APY or effective rate.
- Ignoring inflation, taxes and fees when judging a real return.
- Entering a percentage as a decimal (5 instead of 0.05 is correct here).
Inputs explained
| Field | What to enter |
|---|---|
| Value in the initial week | A number |
| Value in the following week | A number |
| Value after several weeks | A number |
| Number of weeks between initial and that value | A number |
What each result means
- Week over week change = ([Value in the following week] – [Value in the initial week])÷[Value in the initial week]×100
- Absolute change = [Value in the following week] – [Value in the initial week]
- Weekly compound growth rate = (([Value after several weeks]÷[Value in the initial week])^(1÷[Number of weeks between initial and that value]) – 1)×100
- Annualized (52 weeks) at that growth = ((1 + [Weekly compound growth rate]÷100)^52 – 1)×100
Example values
How the main result changes when Value in the initial week changes and everything else stays at the example values above:
| Value in the initial week | Week over week change (%) |
|---|---|
| 600 | 115 |
| 900 | 43.33 |
| 1,200 | 7.5 |
| 1,500 | -14 |
| 1,800 | -28.33 |
| 2,400 | -46.25 |
Formula
WoW change = (this week − last week) ÷ last week × 100Weekly compound growth = (final ÷ initial)^(1 ÷ weeks) − 1Worked example
Inputs — Value in the initial week: 1,200; Value in the following week: 1,290; Value after several weeks: 1,800; Number of weeks between initial and that value: 6.
Results — Week over week change = 7.5 %; Absolute change = 90; Weekly compound growth rate = 6.99 %; Annualized (52 weeks) at that growth = 3,258.34 %.
Frequently asked questions
How do I calculate week over week growth?
(This week − last week) ÷ last week × 100.
What is a good weekly growth rate?
For early startups, 5–7% a week is considered strong.
Why use compound growth over several weeks?
It smooths week-to-week noise.
What formula does the Week over Week Calculator use?
WoW change = (this week − last week) ÷ last week × 100.